layers:Fix cut-and-paste bug
layers:Fix cut-and-paste bug

From Mikko at Unity, there was a cut-and-paste bug here where color
counts were being used to check input attachments. Use input counts
instead.

KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers